In Depth

Quantum computing: The next information revolution

An artist's conception of an array of spin qubits based on subatomic nuclear memory. (Illustration by Peter Allen, courtesy of David Awschalom, UCSB)

Curiosity drives humanity. When confronted with a new phenomenon, we are compelled to search for understanding. We can then control the science with new technologies, making life easier. This, says AAAS Fellow Raymond Laflamme, grants us time to be curious.

In the rapidly evolving field of quantum computing, curiosity over the last hundred years has driven scientists to the brink of controlling this once exotic world.

Quantum computers, with the capacity to complete in an instant calculations that a classical computer with all the time and energy in the universe could never solve, will propel the next information revolution. Yet the concept of quantum computing is young and, so far, no scientist can predict with certainty when that revolution will occur.

For one AAAS fellow and his team of researchers, the missing tool to jump-start this revolution may be found in diamonds.

The subatomic ocean

Observations and theories in quantum mechanics have led to stories of subatomic particles breaking all known laws of classical physics, essentially walking through walls, teleporting across vast distances and traveling back in time.

Quantum particles can occupy two states at the same time. Incredibly sensitive, their characteristics change in the simple process of observing them. Yet in measuring the interactions of particles with higher mass, experimenters can calculate minute energy fluctuations, allowing a better understanding of this quantum soup.

“Quantum mechanics tells you that the quantum [computing] bit or the quantum coin can be both tails and heads at the same time. And this is really changing how the world works,” says Laflamme, the executive director of the University of Waterloo’s Institute for Quantum Computing.

An early scientist to envision a computing system to harness the nature of quantum physics, Richard Feynman, a renowned physicist and mathematician, suggested in 1982 that the strange ability of quantum particles to occupy multiple states—known as superposition—would theoretically allow for parallel calculations. The idea presented a method far more efficient for solving certain problems than the linear factoring system of classical computing that is based on 1s and 0s.

“We already have the technology to harness a small part of the quantum world. That’s what lasers are and that’s what magnetic resonance imaging is,” says Laflamme. “We want to go further than this and there’s quite a big ocean. So now that we have dipped our big toe in the water of the ocean of the quantum world, we try to go deeper.”

Yet this pursuit has been obstructed by defects found in the nanostructures of traditional computers—imperfections magnified exponentially on the quantum scale. This led physicists in the field to scoff at the idea of being able to contain and control these particles.

In five years—a comparative leap in the long history of quantum research—that thinking changed.